Capacitive structures are used as electronic elements in integrated circuits such as Logic devices, CMOS image sensors (CIS), radio frequency integrated circuits (RFIC), monolithic microwave integrated circuits (MMIC), and etc. Capacitive structures include, for example, metal-oxide-semiconductor (MOS) capacitors, p-n junction capacitors and metal-insulator-metal (MIM) capacitors. For some applications, MIM capacitors can provide certain advantages over MOS and p-n junction capacitors because the frequency characteristics of MOS and p-n junction capacitors may be restricted as a result of depletion layers that form in the semiconductor electrodes. An MIM capacitor can exhibit improved frequency and temperature characteristics.
An MIM capacitor includes a dielectric layer disposed between lower and upper electrode plates. The desired capacitance density is usually increased with increased integrated circuit density in dimension scaling. The capacitance density, however, may not be simply increased by stacking more electrode plates due to the area loss resulted from contact vias for electrically connecting each of the electrode plates.